A semiconductor device having high reliability is provided. The semiconductor device includes a transistor and an insulator placed so as to surround the transistor; the insulator has a barrier property against hydrogen; the transistor includes an oxide and a conductor; the conductor includes nitrogen and a metal; the conductor has a physical property of extracting hydrogen; the conductor includes a region having a hydrogen concentration higher than or equal to 2.0×1019 atoms/cm3 and lower than or equal to 1.0×1021 atoms/cm3; and at least part of hydrogen atoms included in the region is bonded to a nitrogen atom.